The present invention relates to liquid pumps and vaporizers, and more particularly to an improved liquid delivery and vaporization system including a novel positive displacement pump assembly for delivering a continuous volume flow at a constant rate to-an improved vaporizer assembly for flash vaporizing the liquid.
Many processes are known where corrosive, sometimes pyrophoric, liquid materials must be vaporized so that the gas vapors can be subsequently used in carefully controlled amounts in a process chamber as a part of a carefully environmentally controlled process. Because of the toxic and dangerous nature of these materials, systems for delivering the liquids to the vaporizer, as well as the vaporizer itself, must be carefully sealed to prevent the escape of the materials. Various such systems are known. One type of system automatically fills the liquid into a bottle. The bottle is heated in order to increase the vapor pressure in the bottle up to a sufficient pressure so that a thermal mass or pressure based flow meter can be used to measure and control the flow of the gas. In some of these systems inert gas is also bubbled through the liquid in order to help carry off more vapor. Such systems tend to be relatively expensive and cumbersome, with vapor flow lines requiring extensive heating to prevent condensation.